How do I repair the music box in a toy jewelry box?

My girlfriend has a toy jewelry box (the kind that has a spinning ballerina) that has alot of sentimental value and doesn’t work properly. This has a Weenie the Pooh instead of ballerina, and the best way I can describe this is "Pooh on crack." The music plays very fast, and Pooh spins so fast that the figure thrashes around and has actually scratched the mirror from hitting it so hard.